This invention relates to a mechanical operator for a two-way gang plow. Such plows include a plow frame supporting a plurality of double-ended plows for use when plowing a field in opposed directions from one end to the other. Two-way plows require a mechanism to swing the plow frame from one side to the other, as well as the further ability to move the plow frame to an upright position for travel purposes.
Various arrangements have been previously proposed for accomplishing such movement. In U.S. Pat. No. 3,749,178 to Watts, a pair of cylinders acting in tandem is used to assure full 180.degree. movement. In U.S. Pat. No. 2,882,979 to Chandler, the movement of a transverse cylinder is converted to rotational movement through a pair of intermeshing segmented gears. U.S. Pat. No. 2,943,689 shows power being supplied for direct rotation of a pivot shaft through a rotatable driving sprocket and a connecting chain. However, as such plows become larger and heavier, transmission of direct rotational power becomes much more difficult and expensive.
U.S. Pat. No. 3,196,955 discloses a prior mechanical apparatus for converting the movement of a single cylinder to the required angular movement of the plow frame for a two-way gang plow. However, the torque applied to the pivot shaft during such movement is not constant. It varies with the separation of the pivotal axes in a lost-motion connection between an operational lever and a crank arm mounted to the pivot shaft for the plow frame. The apparatus includes several interconnected linkages for applying straight line movement from the cylinder assembly, and further incorporates the mechanical disadvantages of a lost-motion connection, which requires sliding bearings in addition to the rotational bearings needed for angular movement.